We’re being asked to arrange the gases (from slowest to fastest) of __average molecular speed.__

When calculating for root mean square speed (μ_{rms}), we will use the following equation:

$\overline{){{\mathbf{\mu}}}_{{\mathbf{rms}}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}\sqrt{\frac{\mathbf{3}\mathbf{RT}}{\mathbf{M}}}}$

µ_{rms} = rms speed,

R = 8.314 J/(mol·K)

T = temperature, K

M = molar mass, kg/mol

At 300K, what is the correct ordering (from slowest to fastest) of average molecular speed of the following gases: Ar, HBr, SO_{2}, and CO_{2}?

A) HBr < SO_{2} < CO_{2} < Ar

B) Ar < CO_{2} < SO_{2} < HBr

C) Ar < HBr < SO_{2} < CO_{2}

D) HBr < CO_{2} < SO_{2} < Ar

E) All these gases have the same average speed at the same temperature

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